Gas Chromatographic Analysis Research Articles

Biyorafineri konseptiyle Rhodobacter sphaeroides O.U.001 ile biyolojik hidrojen ve bakteriyel karotenoid üretimi

In this study, the goal was to produce biohydrogen and bacterial carotenoids with Rhodobacter sphaeroides O.U.001, a purple non-sulfur photosynthetic bacterium, utilizing sugar beet molasses in the context of biorefinery. First, media with different sugar concentrations (10 g/L, 20 g/L, 30 g/L, 40 g/L, 50 g/L) were prepared for bacterial growth. Then, hydrogen production was carried out using these media in anaerobic conditions in 100 ml bioreactors. After hydrogen gas was collected from the bioreactors, carotenoid extraction was performed from the remaining bacteria. As a result of the analyzes, it was found that the amount of biohydrogen and the amount of bacterial carotenoids obtained were inversely proportional to the increased sugar concentrations. The maximum hydrogen formation was detected in the medium containing 10 g/L of sugar (19.18 mL). According to the results of gas chromatography analysis, the quantity of hydrogen in the total gas was found to be around 23.6%. The highest yield of carotenoids was again obtained from bacteria reproduced in a medium containing 10 g/L of sugar (3.12 mg/g, carotenoid/dry biomass). As a conclusion, this study provides an example for the successful realization of two high value-added products within a biorefinery approach by using molasses obtained at an affordable cost.

Thermal desorption processes of H2 and CH4 from Li2ZrO3 and Li4SiO4 materials absorbed H2O and CO2 in air at room temperature

The thermal desorption processes of hydrogen (H2) and methane (CH4) from lithium-based materials, Li2ZrO3 and Li4SiO4, exposed to air at room temperature of 293 K with a relative humidity of 80%, were investigated using gas chromatography (GC). The GC analysis revealed that the absolute values of the released H2 and CH4 gases at 523 K were approximately 7.42 × 10−6 and 1.54 × 10−6 ml/g for Li2ZrO3, and 3.24 × 10−6 and 0 ml/g for Li4SiO4. The amounts of H2 and CH4 released increased with increase in annealing temperatures and considerably depended on absorption properties of water (H2O) and carbon dioxide (CO2) present in air at room temperature. The production of CH4 at low temperature is due to the intermediate species including CHx precursors produced by the reaction between H split from H2O and Li2CO3 resulting in the CO2 absorption of Li2ZrO3 and Li4SiO4 materials.

Hydrocarbon biodegradation by Proteus and Serratia strains isolated from oil-polluted water in Bonny Community, Niger Delta, Nigeria

Two indigenous hydrocarbon utilizing bacteria strains, designated as TKZ and QGR were isolated in oil rich Niger Delta of Nigeria. Determination of the nucleotide sequence of the gene encoding 16S rRNA allowed TKZ and QGR to be identified as Proteus vulgaris and Serratia marcescens. Hydrocarbon degradation potential of the strains was confirmed on hydrocarbon mineral salts medium (1 %, v/v) at 37 °C. Assessment of oil degradation capability of the isolates was monitored using gas chromatographic analysis (GC). The ability of the strains to utilize benzene, diesel, kerosene, and naphthalene was also studied. The results show maximal increase in optical densities at 540 nm and total viable counts was proportional with decrease in pH of the culture media. Percentage degradation in the culture medium showed that the two isolates exhibited biodegradation efficiency above 90 % for kerosene. The two bacterial strains also possess a plasmid of about 9.1 kb size which is suspected to influence the bacterium’s hydrocarbon degradation potential.

Parameter optimization for enhanced biodiesel yield from Linum usitatissimum oil through solar energy assistance

Biodiesel is a biofuel produced from vegetable oils and animal fats. The study describes the solar-assisted biodiesel production from linseed oil and the parameter optimization using Taguchi’s L27 orthogonal approach and response surface methodology (RSM). A solar paraboloid dish of collector area 6.1 m2 and concentration ratio approx. 200 is used for the transesterification process. Yearly and daily solar radiation data shows that May–June has more extended solar radiation availability during the daytime and are favorable months for experimentation. Results show that Taguchi’s approach gives a maximum biodiesel yield of 89.14%, while the RSM model offers a slightly higher 91.9% yield. However, the RSM analysis predicted 91.1% (maximum biodiesel yield) at molar ratio (MR) 8.92:1, reaction time (RT) 108.97 min, and catalyst concentration (CC) 0.61 wt%, respectively. ANOVA analysis found that the MR has the highest percentage contribution of 75.67%, followed by CC (15.9%) and RT (5.69%). Biodiesel composition is determined using gas chromatography and FTIR analysis, and the various other fuel properties are measured as per ASTM testing methods. The study successfully confirms the use of solar heating for the transesterification process.

Experimental Evaluation of Shale Oil Development Effectiveness by Air Injection

In recent years, as an important part of unconventional resources, the effective development of shale oil has been a key area of research in petroleum engineering. Given the widespread availability and low cost of air, the evaluation of air injection in shale reservoirs is a topic worth exploring. This paper analyzes the production performance of different methods of air injection development in the shale reservoir, including air flooding and air huff and puff (HnP), based on full-diameter core air injection experiments. Meanwhile, the characteristics of the residual oil and produced oil are revealed by forming a systematic evaluation method that includes nuclear magnetic resonance (NMR), laser scanning confocal microscopy (LSCM), and gas chromatographic (GC) analysis. The results show that air flooding development is characterized by early gas breakthrough, long oil production period, and “L” shape oil production decline; while air HnP is characterized by first producing gas and then producing oil, rapid oil production, and high oil recovery efficiency in the first round. Compared with air flooding, the replacement efficiency of the first round of air HnP is significantly higher, demonstrating higher feasibility of air HnP in the early stages of development, although the cumulative recovery of three rounds air HnP (17.17%) is lower than that of air flooding (23.36%). The large pores (T2 > 10 ms) are the main source of air injection recovery, while the residual oil is mainly concentrated in the medium pores (1–10 ms). Air injection development has a higher recovery factor for light components (C15−), resulting in a higher level of heavy components in the residual oil. This paper discusses the feasibility and development effectiveness of air injection in shale oil reservoirs, and its development characteristics are further clarified.

Benoxacor is enantioselectively metabolized by microsomes and cytosol from the human liver

Benoxacor is a safener added to current-use herbicide formulations to protect the target crop from herbicidal toxicity. It is an emerging environmental contaminant that has been detected in surface waters, raising the possibility of human exposure via drinking water. Because it is not subject to the same regulations as active pesticide ingredients, its metabolism and toxicity in humans have not been studied. Here we investigate the enantioselective metabolism of benoxacor in human subcellular fractions. Pooled human liver microsomes (pHLM) and cytosol (pHLC) were incubated with racemic benoxacor for up to 30-min. Gas chromatographic analyses were used to measure the enantioselective depletion of benoxacor. pHLMs with and without nicotinamide adenine dinucleotide phosphate (NADPH, co-factor for cytochrome P450 enzymes [CYPs]) and pHLC with glutathione (GSH, co-factor for glutathione S-transferases [GSTs]) metabolized benoxacor. These results demonstrate that microsomal CYPs, microsomal carboxylesterase (CESs), and cytosolic GSTs metabolize benoxacor. Females were predicted to have a higher clearance of benoxacor by GSTs than males. Male and female pHLM incubations with NADPH showed enrichment of the first eluting benoxacor enantiomer (E1-benoxacor). pHLM incubations without NADPH and pHLC incubations with GSH showed an enrichment of the second eluting enantiomer of benoxacor (E2-benoxacor). Our results indicate that human hepatic microsomal and cytosolic enzymes enantioselectively metabolize benoxacor, a fact that needs to be considered when investigating human exposures and toxicities of benoxacor.

Chromatographic Separation of Aromatic Amine Isomers: A Solved Issue by a New Amphiphilic Pillar[6]arene Stationary Phase.

In this work, the fabrication, synthesis, and characterization of a new stationary phase based on an amphiphilic pillar[6]arene (P6A-C10-2NH2) for gas chromatographic analyses are reported. The gas chromatography (GC) column prepared with P6A-C10-2NH2 stationary phase exhibited a medium polarity, an efficiency of 3219 plates/m, and unmatched resolving capabilities toward chloroaniline, bromoaniline, iodoaniline, and toluidine isomers. Furthermore, the P6A-C10-2NH2 column showed excellent repeatability with maximum relative standard deviations equal to 0.02, 0.07, and 2.56% for run-to-run, day-to-day, and column-to-column, respectively, demonstrating a great potential as a new stationary phase in separation science.

Elemental composition, total fatty acids, soluble sugar content and essential oils of flowers and leaves of Moringa oleifera cultivated in Southern Portugal

The evaluation of the elemental content of moringa leaves and flowers by Energy Dispersive X-Ray Fluorescence Spectrometry revealed that the leaves are a good source of some macro (Ca and K) and micronutrients (Mn) beyond the presence of important polyunsaturated fatty acids (PUFAs), essential in human nutrition. Total soluble sugars prevail in the flowers which may be linked to insect attraction and the pollination process. M. oleifera leaves, flowers and seeds essential oils (EOs) were isolated by hydrodistillation. Gas chromatography and gas chromatography-mass spectrometry analysis (GC-MS) showed EOs dominated by alkanes and fatty acids in diverse ratios in the analyzed plant parts. The nutritional characterization of M. oleifera cultivated in Portugal showed some important nutrients to human physiology. Further studies will allow determining if its consumption may overcome the nutritional imbalances of daily modern households, preventing the emergence of hypertension and diabetes.

Isolation and Identification of Constituents Exhibiting Antioxidant, Antibacterial, and Antihyperuricemia Activities in Piper methysticum Root

The aqueous extract of kava (Piper methysticum) root is known as a traditional beverage for daily intake in the Western Pacific Islands, such as Fiji, Tonga, and Vanuatu, to induce relaxation and health-beneficial effects. In this study, the antioxidant, anti-hyperuricemia, and antibacterial properties of kava root were investigated through the isolation and purification of bioactive compounds in ten fractions separated by column chromatography (CC). They included six flavonoids, 5-hydroxy-4',7-dimethoxyflavanone (C1), matteucinol (C2), isosakuranetin (C3), 5,7- dimethoxyflavanone (C4), 2',4'-dihydroxy-6'-methoxydihydrochalcone (in MC5) and alpinetin (C10), and seven kavalactones, 5,6-dehydrokawain (DK) (in MC5 and C6), kavain (in MC7), yangonin (in MC7 and C8), dihydro-5,6-dehydrokavain (DDK) (in MC9), 7,8-dihydromethysticin (in MC9), dihydromethysticin (in MC9), methysticin (in MC9). The chemical structures of the compounds were illustrated by the analyses of gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), nuclear magnetic resonance (1H and 13C-NMR), and X-ray diffraction. The evaluation of the free radical scavenging activity of the isolated substances via the DPPH and ABTS assays revealed that C3 (IC50: ABTS = 76.5; DPPH = 74.8 µg/mL) possessed the strongest antioxidant property. In terms of anti-hyperuricemia activity evaluated via the xanthine oxidase inhibitory in vitro assay, the compound C10 was the most promising inhibitor, revealing an IC50 of 134.52 µg/mL. The two kavalactone mixtures in MC5 and a pure compound C6 inhibited the growth of bacteria Listeria monocytogenes, while MC7 can constrain the development of Klebsiella pneumoniae. This is the first study to isolate, purify, and identify the flavonoids isosakuranetin, 2',4'-dihydroxy-6'-methoxydihydrochalcone and alpinetin in kava root and report their pharmaceutical potential. The identified bioactive compounds showed potent antioxidant, anti-hyperuricemia, and antibacterial activity and thus can enhance the value of beverages and foods derived from kava root.

Characterization of a Methanogenic Microbial Consortium from a Coal Mine in Bogotá Basin

The work studied the methanogenic microbial consortium in a coal mine from the Bogotá basin in Colombia. Ex situ coal-enrichment cultures were established for in vitro growth and de novo gas production. Biogenic gas produced by cultures was analyzed by gas chromatography using thermal conductivity and flame ionization detectors. Cultures were used to isolate microbial specimens and to generate 16S rRNA gene libraries employing bacterial and archaeal primer sets. The gas chromatographic analysis showed methane production at 37 oC, but not at 60 oC, where CO2 was the major component of the biogenic gas. 16S rRNA gene sequence analysis of microbial isolates and clone libraries established that the methanogenic microbial consortium was formed by bacteria species from Bacillus and Gracilibacter genera plus archaea from the Methanothermobacter genus. This methanogenic microbial consortium was potentially responsible for biogenic gas generation in La Ciscuda coal mine. The results suggested that these methanogens produced methane by hydrogenotrophic or CO2 reduction pathways.

High biohydrogen yield from fresh cassava waste pulps via gas dissolution in a dark fermentative environment

The improper disposal of wastes like cassava waste pulps (CWP) in the environment could likely result in putrefaction stench, leachate contamination of water bodies, illnesses/diseases in local populations, and many other adverse effects. This study exploited the use of CWP for the possible production of valuable biofuel such as biohydrogen (bio-H2). Acid hydrolysis was used to prepare the CWP, whereas heat shock was used to prepare the cow dung inoculum. Pretreated organic wastes were used as substrates for dark fermentation, which considered the effects of pH and hydraulic retention duration on bio-H2 generation. The gas chromatography analysis showed 99.89% bio-H2 component of the total biogas produced through dark fermentation. The dissolution of the produced carbon monoxide and carbon dioxide in water enhanced bio-H2 production. At 6.09 pH and 83.24 h HRT, a kilogram of fresh CWP can produce 12.39 ± 0.8 L bio-H2. Overall, the current research has shown that underutilized CWP from starch-producing companies can be used to make sustainable biofuel, which can help to reduce fossil-fuel-related emissions.

A Mass Ratio of Hierarchical H-ZSM5 And Fatty Acid Methyl Ester of Cerbera Manghas Oil and The Effect on The Hydrocarbon Liquid Product Composition

Fossil fuels are classified as non-renewable resources. On the other hand, using fossil fuels has further aggravated the impact of the environmental crisis. The development of alternative fuels that are renewable and renewable is urgently needed in line with the increasing need for fuel. One alternative energy source that can be used in the development of biofuels is Cerbera manghas oil. The catalytic cracking process with 178 g of Cerbera manghas oil can be carried out using hierarchical H-ZSM-5 as a catalyst with a mass of 0.1, 0.2, 0.3, 0.4, and 0.5g at a temperature of 250℃. Gas Chromatography Analysis–Mass Spectrometry (GC-MS) was performed on Cerbera manghas oil and biofuel products. Several hydrocarbons, C7-C12 and C16-C17, with the largest content, were identified as diesel (29.14%) and gasoline (14.08%) using a catalyst mass of 0.5g. So that the use of hierarchical H-ZSM-5 catalyst in the catalytic cracking of Cerbera manghas oil can produce hydrocarbon range gasoline.

Montmorillonite-based polymethacrylate composite monoliths as stationary phase materials for food and pharmaceutical analysis in capillary liquid and gas chromatography

This work relates to the preparation of novel and promising stationary phases containing inorganic-organic composites for capillary liquid and gas chromatography. A naturally occurring montmorillonite was introduced to polymethacrylate monoliths, then used under different conditions of GC and HPLC at the same time. The performance of the columns was evaluated for the separation of alkane and alkylbenzene series in GC and capillary HPLC, respectively. While the bare monoliths failed to separate the model analytes, montmorillonite-based polymethacrylate allowed a full separation of the mixtures with Rs≥1.42. The columns were applied for the determination of myrcene and limonene isomers in the peel extracts of some fruits using GC, and for the analysis of active ingredients including aspirin, vitamin-C, caffeine, and ibuprofen extracted from common drugs using capillary HPLC. In GC, fast separation was achieved in 1.0 min with Rs of 6.53. The columns exhibited the best efficiency for myrcene with 20,900 plates/m. Using the capillary HPLC columns, the active ingredients were resolved in 10 min with Rs≥5.72. The efficiency values located between 12,800–21,700 plates/m in all cases. The developed methods were found to be linear in the range of 0.10–10.0 and 0.20–180 μg/mL for GC and HPLC, respectively. In comparison with commercial columns, the results in GC methods reveal that, despite their much shorter length, the prepared columns proved a faster separation with higher efficiency and comparable detection limits and chromatographic resolution. The prepared HPLC capillaries exposed lower run times and detection limits with comparable efficiency and resolution, and consume fewer samples and mobile phase solvents. The results demonstrate that the montmorillonite-based polymethacrylate composites are applicable as stationary phases for routine analysis and quality control of important fields such as food and pharmaceutical samples.

Composition, Properties, and Utilization of Fumaric Acid Sludge By-Produced from Industrial Phthalic Anhydride Wastewater Treatment

To understand fumaric acid sludge (FAS) systematically and comprehensively and find out how to utilize it, we conducted a series of characterization analyses on FAS. Fourier transform infrared (FT-IR) Spectra shows that the main component of FAS is fumaric acids and also contains a small amount of silicate. The nuclear magnetic resonance hydrogen (1H-NMR) spectrum also shows that fumaric acid accounted for a large proportion of FAS. The X-ray diffraction (XRD) shows that the main phase in FAS is fumaric acid, and there is also a small amount of Kaliophilite. After gas chromatography and mass spectrometry (GC-MS) and pyrolysis gas chromatography and mass spectrometry (Py-GC-MS) analysis, it indicates that the possible volatiles and pyrolysis products in FAS are fumaric acid, maleic acid, maleic anhydride, phthalic acid, etc. In the test of Liquid chromatography and mass spectrometry (LC-MS), we determined the contents of phthalic acid, fumaric acid, and maleic acid in FAS. The detailed mass content of each component in FAS is as follows: phthalic acid is about 0.10-0.15%; maleic anhydride is about 0.40-0.80%; maleic acid is about 18.40-19.0%; fumaric acid is about 55.00-56.90%; succinic anhydride is about 0.06-0.08%; acrylic acid is about 0.06-0.08%; malic acid is about 0.90-1.00%; acetic acid is about 0.10-0.20%; silicate is about 0.25-0.30%; phthalic anhydride is about 0.20-0.30%; water is about 24.30-24.80%. The filtrate loss reducer (PAAF) used in oilwell drilling fluids synthesized by FAS not only has excellent temperature and complex saline resistance, the API filtration loss (FL) was only 13.2 mL/30 min in the complex saline based mud, but is also cost-effective.

Effects of K2CO3 on pyrolysis characteristics of Xinjiang cotton stalk

The horizontal fixed bed pyrolysis method was used in this study to examine the reaction parameters of K in-situ catalytic pyrolysis of the cotton stalk at 600 °C. The pyrolysis conversion mechanism of cotton stalk under the influence of K was investigated in conjunction with gas chromatography analysis, FT-IR analysis, and GC-MS analysis. According to the findings, the gas production of a mixture of 1 g cotton stalks grew from 215 mL (0.0 %- K2CO3) to 275 mL (7.5% -K2CO3), but it was inhibited to 263 mL when K2CO3 addition was at 10.0%. According to the results of the characterization, K2CO3 might accelerate the breakdown of oxygen-containing rings in cellulose and hemicellulose, encourage the conversion of furan structure into ketones, and prevent the transformation of furan into long-chain alkanes. The addition of K2CO3 introduces more K into the cotton stalk. Under the influence of K, long-chain alkanes, phenols, and esters will be further cracked and polymerized to create more stable aromatic hydrocarbons. According to quantum chemical calculations, xylose's oxygen-containing ring opened first without the presence of K, then H transfer, dehydrogenation, dehydration, and cyclization to generate the cyclopentanone structure. The oxygen-containing groups in the xylose side chain preferentially bind to K in the presence of K, and the bond length between the O and C rings of the side chain is lengthened, while without K, the C–O bond length of the preferred ring opening is shortened.

Development and Evaluation of Essential Oil-based Lozenges using Menthol and Eucalyptus and in vitro Evaluation of their Antimicrobial activity in S.aureus and E.coli

The throat lozenegs are most commonly used first line of treatment for relief of various throat infections. The most common ingredient used in the lozenegs are various herbal extracts and essential oil having local action of throat area. in the present studies a essential oil based lozenges were prepared using eucalyptus oil and menthol as active ingredient. Antibacterial activity was evaluated for menthol and eucalyptus oil against human pathogens E.coli and S.aureus. both the sugar based and sugar free base was used to develop two types of lozenges formulation. Quality parameters were evaluated for lozenges formulations such as hardness, friability, dissolving time, and moisture content. Compatibility study was carried out using thin layer chromatography and gas chromatography analysis. The eucalyptus oil and menthol displayed moderate antibacterial activity against E.coli and S.aureus. The lozenges were found to be having satisfactory quality parameters. GC and TLC analysis was found to be a suitable method for identification of menthol and eucalyptus oil in the lozenges. TLC was found to be a simple, quick and simple technique for rapid identification of the essential oil and to confirm the batch-to-batch consistency. 1H-NMR and 13C-NMR was found to be useful tool for rapid identification of essential oils on basis of diagonostic peaks. Overall this study can be used for standard methods for quality control of the essential lozeneges formulation for the new formulation and product available in the market as well.

Biogas digestate as a sustainable phytosterol source for biotechnological cascade valorization.

Every year, several million tonnes of anaerobic digestate are produced worldwide as a by-product of the biogas industry, most of which is applied as agricultural fertilizer. However, in the context of a circular bioeconomy, more sustainable uses of residual digestate biomass would be desirable. This study investigates the fate of the sterol lipids β-sitosterol and cholesterol from the feedstocks to the final digestates of three agricultural and one biowaste biogas plants to assess if sterols are degraded during anaerobic digestion or if they remain in the digestate, which could provide a novel opportunity for digestate cascade valorization. Gas chromatographic analyses showed that feedstock sterols were not degraded during anaerobic digestion, resulting in their accumulation in the digestates to up to 0.15% of the dry weight. The highest concentrations of around 1440 mg β-sitosterol and 185 mg cholesterol per kg dry weight were found in liquid digestate fractions, suggesting partial sterol solubilization. Methanogenic batch cultures spiked with β-sitosterol, cholesterol, testosterone and β-oestradiol confirmed that steroids persist during anaerobic digestion. Mycobacterium neoaurum was able to transform digestate sterols quantitatively into androstadienedione, a platform chemical for steroid hormones, without prior sterol extraction or purification. These results suggest that digestate from agricultural and municipal biowaste is an untapped resource for natural sterols for biotechnological applications, providing a new strategy for digestate cascade valorization beyond land application.

Phosphorus, stable isotopes and fatty acids of soils as tools for recognizing a Bronze Age droveway in the Valli Grandi Veronesi (North Italy)

This study focuses on the surroundings of the terramara of Castello del Tartaro in the lowland of Valli Grandi Veronesi (North Italy) outside a Bronze Age village enclosed by channels and embankments, where two groups of double parallel side drainage ditches running from northwest to southeast were found. This evidence has been interpreted as a “Big Road” and more precisely a droveway, possibly used for the passage of cattle. The road was sampled along a section, at 4 different levels of depth, and the content in inorganic and organic phosphorous was assessed. In the sampled section the content of phosphorus shows the presence of discontinuities and strong phosphorus accumulation in the layers under the arable land. The analysis of the stable isotopes of carbon and nitrogen attests to traces of herbivores, while the comprehensive two-dimensional gas chromatography analysis identified a high number of significant fatty acids suggesting the presence of fats from ruminant animals. The results, as a whole, corroborate the hypothesis of a droveway. This hypothesis agrees with both paleobotanical and zooarcheological data from the territory around the embanked settlements. This study thus underlines the importance of cattle husbandry within the complex commercial relationships that characterized the Bronze Age.

Effect of pH and Ozone Dosage on Characteristic of Ozonated Rice Bran Oil


 
 
 The influence of pH and ozone dose, as well as ascorbic acid addition during the ozonation process, on the properties of Rice Bran Oil (RBO), was examined. The spectroscopic characteristic of RBO before and after ozonation was analysis directly, while the physicochemical property was assessed by density, viscosity, pH, iodine number, peroxide number, and acid number. With an increase in ozone dose, the carbon double bond in the RBO reduced. The primary product of the ozonation process is ozonide, and one of its by-products is 1,2,4-trioxolane, which contains a carbon single bond as a result of the ozonation reaction. According to this study, the pH 4 and ozone dose of 440 mg O3/L are the optimum parameters utilized in the RBO ozonation process. RBO's density and viscosity were 0.918 g/mL and 0.042 cP, respectively, at these conditions. Its iodine number, acid number, and peroxide number were also 3.173 g/g RBO, 2.3 mg NaOH/g RBO, and 55 mgeq/kg, respectively. Analyses of gas chromatography and nuclear magnetic resonance spectroscopy revealed the presence of 1,2,4-trioxolane. Ozone dosage is critical because greater ozone concentrations place RBO in a saturated state, making the 1,2,4-trioxolane unstable and readily destroyed, whereas lower temperatures can avoid this.
 
 

Multifaceted Bacillus spp. for the management of cotton bacterial blight caused by Xanthomonas citri pv. malvacearum

Bacterial antagonists against plant pathogens are widely exploited for the biological management of plant diseases. In the present study, antagonists were isolated from cotton plant associated bacteria such as endophytes (74 isolates), phylloplane (32 isolates) and cotton rhizosphere soils (48 isolates). Their efficacy against X. citri pv. malvacearum (Xcm) were evaluated in vitro by agar well diffusion technique. Among the isolates, the endophyte Bacillus amyloliquefaciens strain ETL2 was very effective in inhibiting the Xcm growth with an area of 983.76 mm2 followed by Bacillus velezensis strain ELS2 with an area of 944.41 mm2. PCR amplification of antimicrobial peptide (AMP) genes revealed that B. amyloliquefaciens strain ETL2 had maximum of 8 antibiotic biosynthesis genes namely, ItuC, bacA, bacD, bamC, fenCEA, sfrA, spaCS and mycC that produced antibiotics Iturin, bacilysin, bacillomycin, fengycin, surfactin, subtilin and mycosubtilin. Further, B. amyloliquefaciens strain ETL2 associated with Xcm inhibition was identified as aromatic hydrocarbons, phenols and fatty acids by Gas chromatography and mass-spectrometry (GC–MS) analysis of culture extracts. Delivery of B. amyloliquefaciens strain ETL2 and B. velezensis strain ELS2 as seed treatment and foliar spray was found promising for the management of bacterial blight of cotton in pot and field experiments. In pot and field experiments, the maximum plant growth promotion and seed cotton yield were observed in the plants treated with B. amyloliquefaciens strain ETL2 followed by B. velezensis strain ELS2 with better disease control efficiency compared to chemical control agents and chemical plant defense inducers.